Chronic thromboembolic Pulmonary hypertension(CTEPH) is characterized by obstruction of the pulmonary vasculature, leading to increased pulmonary vascular resistance, progressive pulmonary hypertension (PH) and right ventricular failure- most common cause of death for patients with PH. Riociguat, (ADEMPAS) is a member of a new class of drug recently approved in Canada for the treatment of CTEPH.